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High-flow nasal oxygen versus conventional oxygen therapy in patients with hypoxemic COVID-19 pneumonia: A randomized controlled trials based meta-analysis

Cao Zheng, Jieyan Zhu, Zhi-Jun Lu, Liya Jiang, Fang-Liang Chen, Wenxiong Zhang, Ying Jiang

Respiratory Medicine, 2026

2,528 participants

Abstract

BACKGROUND

Although the COVID-19 pandemic has ended, severe cases of COVID-19 pneumonia (pneumonia caused by SARS-CoV-2) are still common in clinical practice. These patients frequently suffer from hypoxemia, for which conventional oxygen therapy (COT) may be insufficient. High-flow nasal oxygen (HFNO) provides enhanced oxygen delivery, but its overall clinical benefits remain uncertain. Our meta-analysis assesses HFNO's effectiveness and safety compared to COT for treating COVID-19-related hypoxemia by combining data from RCTs.

METHODS

We thoroughly explored six databases to identify suitable RCTs that examined HFNO versus COT in COVID-19 hypoxemic patients. Mortality and intubation were the main outcomes, while secondary outcomes included hospitalization indicators and blood gas monitoring indicators following oxygen therapy.

RESULTS

Eight RCTs involving 2528 patients were included. HFNO therapy demonstrated significantly lower rates of total intubation (Risk ratio: 0.86 [0.78, 0.95], P = 0.003), as well as intubation at 7, 14, and 28 days compared with COT. Additionally, the HFNO group showed a shorter time to oxygen therapy de-escalation (MD: 3.53 [-4.50, -2.55] days, P < 0.00001). After oxygenation therapy, the HFNO group exhibited a lower respiratory rate (MD: 2.77 [-3.67, -1.88] breaths/min, P < 0.00001), PaCO2 (MD: 1.00 [-1.67, -0.33] mmHg, P = 0.003), and a higher SpO2/FiO2 ratio (MD: 47.00 [34.77, 59.23], P < 0.00001). Similar baseline characteristics and mortality…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 2,528 participants or records.

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